Functionalized copolymers of isoolefins and diolefins and their use as compatibilizers

Abstract

Functionalized copolymers of isoolefins and conjugated diolefins, methods of preparing the copolymers, and their use as compatibilizers are disclosed. The diolefin monomer units of the co-polymer are modified at the C—C double bond along the backbone of the copolymer to include an oxygen containing functional group such as epoxide, ester or alcohol. The functionalized copolymers improve the wettability of a non-hydrophilic surface towards hydrophilic polymer and allows for the formation of homogenous layers of the hydrophilic polymers. In particular, the spreading of a hydrophilic polymer on a non-hydrophilic substrate is facilitated by applying the co-polymers as an interfacial layer between the two incompatible materials. The resulting coated substrates exhibit resistance to protein adsorption and cell growth after grafting. The co-polymers are especially suited in the coating of biomedical devices where a high degree of uniformity of the coated surface is required.

What is claimed is: 
     
         1 . A compatibilizer for increasing the wettability of substrate surface, the compatibilizer comprising a functionalized copolymer comprising repeating units derived from at least one C4-C8 isoolefin and repeating units derived from at least one C4-C16 conjugated diolefin, wherein the copolymer comprises one or more units derived from the at least one conjugated diolefin wherein a C—C double bond along a backbone of the copolymer is functionalized with an oxygen containing functional group. 
     
     
         2 . The compatibilizer of  claim 1 , wherein the oxygen containing functional group is epoxide, hydroxyl, or —OC(O)—R, wherein R is H, C 1-6  alkyl, C 1-6  alkyl substituted with —O—C 1-6  alkyl, —C(O)R′ or —O—C 1-6  alkyl-C(O)R′, where R′ is H, OH, C 1-6  alkyl or —O—C 1-6  alkyl. 
     
     
         3 . The compatibilizer of  claim 1 , wherein the oxygen containing functional group is OC(O)—R, wherein R is H, C 1-6  alkyl, optionally substituted with —O—C 1-6  alkyl, —C(O)R′ or —O—C 1-6  alkyl-C(O)R′, where R′ is H, OH, C 1-6  alkyl or —O—C 1-6  alkyl. 
     
     
         4 . The compatibilizer of  claim 1 , wherein the functionalized copolymer comprises one or more functionalized isoprene units represented by the formula: 
       
         
           
           
               
               
           
         
       
       where R is H, C 1-6  alkyl, optionally substituted with —O—C 1-6  alkyl, —C(O)R′ or —O—C 1-6  alkyl-C(O)R′, where R′ is H, OH, C 1-6  alkyl or —O—C 1-6  alkyl. 
     
     
         5 . The compatibilizer of  claim 1 , wherein the copolymer has a weight average molecular weight of 250,000 to 1,500,000 g/mol. 
     
     
         6 . The compatibilizer of  claim 1 , wherein the copolymer comprises about 1 to about 20 mol % of the repeating units derived from the conjugated diolefin and about 80 to 99.5 mol % of the repeating units derived the isoolefin. 
     
     
         7 . The compatibilizer of  claim 1 , wherein the copolymer comprises isobutylene. 
     
     
         8 . The compatibilizer of  claim 1 , wherein the compatibilizer comprises 3 to 100% of the functionalized isoprene units.